1. Field of the Invention
The present invention relates to a monitoring device, and more particularly, to a monitoring device characterized by a technique combined by a tour monitoring process and an unmoving object monitoring process.
2. Description of the Related Art
In recent years, a monitoring device (a monitoring system) for monitoring a suspicious person and an unidentified object from a remote place has been vigorously developed and manufactured to increase security in ordinary houses, offices and public facilities.
As a general monitoring unit of this kind of the monitoring device, there has been known a tour monitoring unit provided with an image pickup unit (a photographing unit) with a zooming function, a pan mechanism for horizontally rotating the image pickup unit and a tilt mechanism for vertically rotating the image pickup unit. The tour monitoring unit picks up images at a plurality of registered spots every constant time interval, for example, in a predetermined order (refer to Japanese Laid-Open Patent Publication (Kokai) No. 2002-290789, for example).
There has also been known an unmoving object monitoring unit which determines that an object is unidentified when the object appears in an image pickup area previously captured as a background image and notifies a user (an administrator) of the unidentified object. The unmoving object monitoring unit performs the above determination and notification when a picked up image is different from the background image due to the appearance of the object or the difference continues for a constant time interval (refer to Japanese Laid-Open Patent Publication (Kokai) Nos. 06-105312 and 2007-300531, for example).
When a single monitoring device configured by combining the above two monitoring units is operated, the determination needs to be performed before the tour monitoring unit causes the image pickup unit to pass a monitoring spot in order that the unmoving object monitoring unit determines that an object left unattended is unidentified.
In other words, a tour monitoring time of the tour monitoring unit needs to be set longer than an unmoving object monitoring time of the unmoving object monitoring unit. Such a mutual dependence of both units on each other imposes restrictions on the user in using the monitoring device.
That is to say, the tour monitoring time needs to be set shorter to quickly detect an object left unattended. On the other hand, the notification following the determination that an object left unattended is unidentified is sometimes wrong, so that the unmoving object monitoring time needs to be set longer to reduce such a wrong notification. At this point, the above restrictions cause a problem.